TECH TIP: Never change the hammer spring only or misfires are certain or lite strikes are almost certain. For firing pin block CZ, the correct FP spring is 97041. For all others, Shadow 1 & 2 and most non-firing pin block CZ’s, use FP spring 97045.
NOTE: HS-12000 is a competition spring and is not recommended for any self-defense application. HS-12000 is designed to be used with Federal and Winchester primers, other brands of primers may not run 100%. We suggest you thoroughly range test this spring with other primers to verify reliable ignition.